Method, apparatus and system for paging processing and information displaying

ABSTRACT

A method, an apparatus, and a system for paging processing and information displaying are disclosed. The paging processing method includes: receiving a paging request message from a Mobile Switching Center (MSC) which a called User Equipment (UE) registers to; and when the called UE is connected, sending a paging notification message to the called UE, and returning a called-UE paging status message to the MSC. In the embodiments of the present invention, after the Mobility Management Entity (MME) receives the paging request message from the MSC, if the called UE is connected, the MME not only sends a Circuit-Switched (CS) paging notification message to the called UE, but also returns a paging status message to the MSC, indicating that the called UE has received the paging notification message.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/710,203, filed on May 12, 2015, which is a continuation of U.S.patent application Ser. No. 13/101,816, filed on May 5, 2011, now U.S.Pat. No. 9,049,677, which is a continuation of International ApplicationNo. PCT/CN2009/074812, filed on Nov. 5, 2009, and the InternationalApplication claims priority to Chinese Patent Application No.200810225981.4, filed on Nov. 7, 2008. The afore-mentioned patentapplications are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to communication technologies, and inparticular, to a method, an apparatus, and a system for pagingprocessing and information displaying.

BACKGROUND

An Evolved Universal Mobile Telecommunication System Territorial RadioAccess Network (E-UTRAN) and an Evolved Packet Core (EPC) make up anEvolved Packet System (EPS), where the Universal MobileTelecommunication System is abbreviated to UMTS. Some operators expectto provide voice services still through the traditional 2G/3G radioaccess network and Circuit-Switched (CS) core network after deployingthe EPS network. The EPS network provides only Packet-Switched (PS) dataservice access. In the foreseeable future, the EPS network will coexistwith the traditional 2G/3G CS network. Most User Equipments (UEs) keep aradio connection of one radio access technology at one moment to reducecosts and battery consumption and save air interface signaling.Therefore, a CS fallback solution is put forward. A UE can access the CScore network through a 2G/3G access network such as the Global Systemfor Mobile Communications (GSM)/GSM Enhanced Data rate for GSM EvolutionRadio Access Network (GERAN) (Enhanced Data rate for GSM Evolution isabbreviated to EDGE), UTRAN, and Code Division Multiple Access (CDMA)Access Network (AN), or access the EPC through an E-UTRAN. After the UEis attached to the EPS, an association is set up between a MobilityManagement Entity (MME) which the UE registers to and a Mobile SwitchingCenter (MSC) in the CS domain which the UE registers to. The interfacebetween the MME and the MSC is defined as an SGs interface in the EPSstandard. After the SGs interface association is set up, the UE mayaccess the EPC on the E-UTRAN to use packet services when no CS voiceservice is in progress. If a voice service needs to be performed, the UEmay fall back to the GERAN/UTRAN/CDMA AN through a CS fallback procedureto set up a CS call link according to the existing CS procedure andperform the voice service, which is known as CS fallback. When the UEperforms the voice service, the packet bearer of the UE is generallysuspended by the network. After the packet bearer is suspended, thenetwork still reserves the IP address of the packet bearer allocated tothe UE, but the packet bearer is unable to transmit packet data at thistime, namely, the data service is interrupted. After the voice serviceof the UE is completed, the network may resume the packet bearer of theUE through a resume procedure, and the UE resumes the packet service.

It is assumed that the UE accesses the CS core network through a UTRAN.After the MME is associated with the MSC at the SGs interface (the setupof the SGs interface association means that the UE accesses the EPCthrough an E-UTRAN currently and registers with the MSC through theEPC), if the MSC receives a UE Initial Address Message (IAM) from thecalling party, the MSC forwards a paging request message to the MME.After the MME receives the paging request message, if the UE iscurrently connected, the MME sends a paging notification message to theUE directly through a signaling connection between the MME and the UE.After receiving the paging notification message, the UE may displayprompt information according to the CS fallback configuration and thecurrent service status on the UE. The prompt information indicates tothe user that a voice call arrives and asks the user whether tointerrupt the current data service and fall back to the CS domain toanswer the voice call. If the UE receives a command input by the userintending to interrupt the current data service and answer the voicecall, the UE may notify the MME to perform a CS fallback procedure, fallback to the CS domain and set up a CS call link for the voice service,and hand over the current packet bearer to the UTRAN and suspend it. Ifthe UE receives a command input by the user intending to reject thevoice call, the UE may send a service request message carrying the causeof rejection to the MME. After receiving the message, the MME notifiesthe MSC that the called user rejects the voice call through an SGsinterface. The MSC responds to the calling party according to a pagingfailure procedure or a UE rejection procedure. In this case, the ongoingUE data service on the E-UTRAN is not affected.

In the process of implementing the present invention, the inventor findsat least these problems in the prior art. After the UE displays theprompt information, the user of the UE needs to confirm whether to“interrupt the current data service and answer the voice call” or“continue the current data service and reject the voice call”. Theconfirmation is a man-machine interaction process. It takes a fewseconds or more for the user of the UE to see the prompt information,make a judgment, and send confirmation information to the UE. After theMSC sends a paging request message to the MME, the MSC keeps waiting fora paging response from the UE. Generally, the waiting time of the MSC isover 10 seconds. In the CS fallback solution, if the MSC fails toreceive the paging response from the UE in a long period because ofwaiting for the confirmation of the CS fallback operation from the user,the MSC is unable to know whether the UE failed to be paged on theE-UTRAN side, or whether the UE is still waiting for the confirmationfrom the user after successfully receives the paging request on theE-UTRAN side. Consequently, the MSC mistakenly believes that the pagingfails, and terminates the call procedure or attempts the paging on the2G/3G access network instead mistakenly. In the existing CS domain,after the called user is paged successfully and a CS call link is setup, an alerting message is returned to the calling party, and thecalling party hears the ring back tone, which takes only a few secondsnormally. In the CS fallback solution, however, while waiting for thecalled user to confirm the CS fallback operation, the calling party mayterminate the call actively because the calling party hears no ring backtone in a long period, and mistakenly believes that the network fails.Thus the voice service is affected.

SUMMARY

Embodiments of the present invention provide a method, an apparatus anda system for paging processing and information displaying to improve thesuccess ratio of paging initiated by an MSC which a UE registers to theUE currently connected on an E-UTRAN.

A paging processing method provided in an embodiment of the presentinvention includes: receiving a paging request message sent by an MSCserver which a called UE registers to; and sending a paging notificationmessage to the called UE when the called UE is connected, and returninga called-UE paging status message to the MSC server.

An information displaying method provided in an embodiment of thepresent invention includes: receiving a paging notification message thatcarries a service type identifier (ID); displaying first promptinformation that instructs a user to confirm whether to accept a CSfallback procedure; obtaining a first instruction, where the firstinstruction is input by the user according to the first promptinformation; triggering execution of the CS fallback procedure accordingto the first instruction; displaying second prompt information accordingto the service type ID and the first instruction, where the secondprompt information instructs the user to confirm whether to put througha call; obtaining a second instruction, where the second instruction isinput by the user according to the second prompt information; andreturning a Connect message to the MSC server to put through the callaccording to the second instruction, or executing an operation procedurecorresponding to the service type ID.

A mobility management apparatus provided in an embodiment of the presentinvention includes: a first receiving module, configured to receive apaging request message sent by an MSC server which a called UE registersto; and a notifying module, configured to send a paging notificationmessage to the called UE when the called UE is connected and after thefirst receiving module receives the paging request message, and return acalled-UE paging status message to the MSC server.

An MSC server provided in an embodiment of the present inventionincludes: a second receiving module, configured to receive a called-UEpaging status message returned by a mobility management apparatus; and aprocessing module, configured to extend time of waiting for a called UEto return a paging response message after the second receiving modulereceives the paging status message.

A UE provided in an embodiment of the present invention includes: athird receiving module, configured to receive a paging notificationmessage that carries a service type ID; a first displaying module,configured to display first prompt information after the third receivingmodule receives the paging notification message, where the first promptinformation instructs a user to confirm whether to accept a CS fallbackprocedure; a first obtaining module, configured to obtain a firstinstruction, where the first instruction is input by the user accordingto the first prompt information; a first executing module, configured totrigger execution of the CS fallback procedure according to the firstinstruction; a second displaying module, configured to display secondprompt information according to the service type ID and the firstinstruction, where the second prompt information instructs the user toconfirm whether to put through a call; a second obtaining module,configured to obtain a second instruction, where the second instructionis input by the user according to the second prompt information; and asecond executing module, configured to return a Connect message to theMSC server to put through the call according to the second instruction,or execute an operation procedure corresponding to the service type ID.

A paging processing system provided in an embodiment of the presentinvention includes: an MSC server, configured to send a paging requestmessage to a mobility management apparatus, receive a called-UE pagingstatus message returned by the mobility management apparatus, and extendtime of waiting for a called UE to return a paging response message; andthe mobility management apparatus, configured to receive the pagingrequest message sent by the MSC server, send a paging notificationmessage to the called UE when the called UE is connected, and return thecalled-UE paging status message to the MSC server.

In the technical solution under the present invention, after the MMEwhich the UE registers to receives a paging request message from the MSCwhich the called UE registers to, if the called UE is connected, the MMEsends a CS paging notification message to the called UE; or returns apaging status message to the MSC, indicating that the called UE hasreceived the paging notification message. In this way, the embodimentsof the present invention improve the success ratio of paging initiatedby the MSC which the UE registers to the UE currently connected on theE-UTRAN.

BRIEF DESCRIPTION OF THE DRAWINGS

To make the technical solution under the present invention clearer, theaccompanying drawings for illustrating the embodiments of the presentinvention or the prior art are described below. Apparently, theaccompanying drawings are exemplary only, and persons having ordinaryskill in the art can derive other drawings from such accompanyingdrawings without any creative effort.

FIG. 1 is a flowchart of a paging processing method provided in a firstembodiment of the present invention;

FIG. 2 is a flowchart of a paging processing method provided in a secondembodiment of the present invention;

FIG. 3 is a flowchart of a paging processing method provided in a thirdembodiment of the present invention;

FIG. 4 is a flowchart of a paging processing method provided in a fourthembodiment of the present invention;

FIG. 5 is a flowchart of an information displaying method provided in afifth embodiment of the present invention;

FIG. 6 shows a structure of a mobility management apparatus provided ina sixth embodiment of the present invention;

FIG. 7 shows a structure of a mobility management apparatus provided ina seventh embodiment of the present invention;

FIG. 8 shows a structure of an MSC server provided in an eighthembodiment of the present invention;

FIG. 9 shows a structure of a UE provided in a ninth embodiment of thepresent invention; and

FIG. 10 shows a structure of a paging processing system provided in atenth embodiment of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The technical solution under the present invention is described belowwith reference to embodiments and accompanying drawings. Evidently, theembodiments described below are exemplary only, without covering allembodiments of the present invention. All other embodiments, which canbe derived by those skilled in the art from the embodiments providedherein without any creative efforts, shall fall within the scope of thepresent invention.

In the CS fallback solution, the overall architecture of the CS fallbacksolution and the idea of the present invention are applicable regardlessof the type of target CS system. For ease of description, it is assumedthat CS fallback occurs before the UE accesses the EPC through anE-UTRAN and after the UE accesses the CS core network through a UTRAN.

FIG. 1 is a flowchart of a paging processing method provided in thefirst embodiment of the present invention. In this embodiment, a calledUE accesses an EPC currently through an E-UTRAN, and an MME which thecalled UE registers to (hereinafter referred to as a called MME) isassociated with an MSC which the called UE registers to (hereinafterreferred to as a terminating MSC) through an SGs interface. As shown inFIG. 1, the method in this embodiment includes the following steps.

Step 101: The MME receives a paging request message sent by theterminating MSC.

Step 102: When the called UE is connected, the MME sends a pagingnotification message to the called UE, and returns a called-UE pagingstatus message to the terminating MSC. While this invention has beendescribed with reference to illustrative embodiments, this descriptionis not intended to be construed in a limiting sense. Variousmodifications and combinations of the illustrative embodiments, as wellas other embodiments of the invention, will be apparent to personsskilled in the art upon reference to the description. It is thereforeintended that the appended claims encompass any such modifications orembodiments.

In this embodiment, after the MME receives the paging request messagefrom the terminating MSC, if the MME finds that the called UE isconnected, the MME not only sends a CS paging notification message tothe called UE, but also returns a paging status message to the MSC,indicating that the called UE has received the paging notificationmessage. In this way, the following case can be prevented and thereforethe call success ratio is improved: The MSC performs an incorrectoperation as a result of mistakenly believing that paging the called UEon the E-UTRAN fails when the called UE waits for the user to confirmexecution of the CS fallback procedure.

FIG. 2 is a flowchart of a paging processing method provided in thesecond embodiment of the present invention. In this embodiment, thecalled UE accesses the EPC currently through an E-UTRAN, and the calledMME is associated with the terminating MSC through an SGs interface. Asshown in FIG. 2, the method in this embodiment includes the followingsteps.

Step 201: The terminating MSC receives an IAM sent by the calling party,where the IAM carries a Mobile Station ISDN (MSISDN) of the called UE.The MSC searches the context of the called UE according to the called UEMSISDN carried in the IAM, and obtains an International MobileSubscriber Identity (IMSI) corresponding to the called UE. The MSC sendsa paging request message to the called MME through the SGs interface,where the paging request message carries the IMSI of the called UE.

The IAM may further carry an ID of the calling UE, for example, theMSISDN of the calling UE. In this case, the paging request messagecarries the ID of the calling UE accordingly.

Step 202: The MME receives the paging request message, searches thecontext of the called UE according to the called UE IMSI carried in thepaging request message, and sends a CS paging notification message tothe called UE through a Non Access Stratum (NAS) message when the MMEdetermines that the called UE is connected according to the statusrecorded in the context of the called UE.

If the paging request message sent by the MSC in step 201 carries the IDof the calling UE, namely, the MME obtains the ID of the calling UE fromthe MSC, for example, the MSISDN of the calling UE, the MME in this stepmay add the MSISDN of the calling UE to the CS paging notificationmessage.

Step 203: The MME returns a called-UE paging status message to the MSC,indicating that the called UE has received the paging notificationmessage and has started a man-machine interaction program.

Step 204: The MSC receives a paging status message, extends time ofwaiting for the CS paging response from the called UE, and returns analerting message (namely, the Address Complete Message, which is ACM forshort) of CS call link setup to the MSC which the calling UE registersto (hereinafter referred to as the calling MSC) according to the presetpolicy so that the calling MSC forwards the alerting message to thecalling UE.

Step 205: The called UE receives a CS paging notification message, anddisplays prompt information according to preset CS fallbackconfiguration information, requesting the user to confirm whether toexecute a CS fallback procedure.

If the CS paging notification message sent by the MME in step 202carries the ID of the calling UE, namely, the called UE obtains the IDof the calling UE from the MME, for example, the MSISDN of the callingUE, the called UE in this step may add the MSISDN of the calling UE tothe prompt information.

Step 206: After receiving an execution command input by the user,namely, a command for terminating the current data service andperforming the voice service, the called UE records a user selection,and sends a service request message to an evolved Node B (eNB).

Step 207: The eNB receives the service request message and forwards itto the MME.

Step 208: The MME receives the service request message, and initiates aCS fallback procedure.

Till this step, the called UE falls back to the CS domain, sets up a CScall link for answering the call, and hands over the current PS bearerto the UTRAN and suspends it.

In step 201 in this embodiment, the ID may be another type of ID thatuniquely identifies the called UE, for example, the Temporary MobileStation Identity (TMSI) of the UE in the CS domain, or MME TemporaryMobile Station Identity (M-TMSI) of the UE in the EPS network, whichshall not be constructed as limitations to the present invention.

In this embodiment, the MSC keeps waiting for the called UE to return aresponse before step 204; the MSC may use two types of message as alegal response to the paging request message sent to the MME:

(a) The user of the called UE chooses to “accept” the CS fallback: Thecalled UE sends a service request in the CS domain, and the MSC uses theservice request message received in the CS domain as a paging response.

(b) The user of the called UE chooses to “reject” the CS fallback, ormakes no confirmation, namely, neither chooses to “accept” the CSfallback nor chooses to “reject” the CS fallback, within a set time(such as 20 seconds): The called UE sends a service request messagecarrying the cause of rejection to the MME. Through an SGs interface,the MME notifies the MSC that the user of the called UE rejects thecall. The MSC returns a response to the calling party, indicating pagingfailure or user rejection.

Unless otherwise specified herein, the response made by the called UE tothe CS paging means that the user of the called UE chooses to “accept”the CS fallback normally, and that the called UE falls back to the 2G/3Gaccess network, and sends a service request message in the CS domain asa CS paging response to the MSC.

In step 204 in this embodiment, after the MSC receives the paging statusmessage, the MSC may return an alerting message to the calling partyaccording to a preset policy. The preset policy may be: The MSC sendsthe alerting message to the calling MSC immediately. Or the presetpolicy is: The MSC forwards the alerting message to the calling MSCafter a preset period, for example, the MSC starts a paging waitingtimer that sets a time limit of 12 seconds. If the MSC still receives noCS paging response from the called UE upon expiry of the paging waitingtimer, the MSC sends an alerting message to the calling party, and goeson waiting for the CS paging response from the called UE. If the MSCreceives a CS paging response from the called UE before expiry of thepaging waiting timer, the MSC may stop the paging waiting timer, and setup a CS call link to the called UE, and return an alerting message tothe calling party.

Step 203 in this embodiment may be performed immediately after step 202;or, after completion of step 202, a timer is started, and step 203 isperformed after expiry of this timer. For example, a 10 s waiting timeris started, and the time limit of this timer should be less than that ofthe paging waiting timer of the MSC, and should be less than the timegenerally spent for the calling MSC and the user of the calling UE inwaiting for the alerting message. The MME sends a paging status messageto the MSC only if the MME still receives no response of accepting orrejecting the CS fallback procedure from the called UE upon expiry ofthe waiting timer on the MME. After receiving the paging status message,the MSC knows that the called UE has actually received the CS pagingnotification message although the CS paging response has not beenreceived from the called UE for a long time, and knows that the calledUE is waiting for confirmation from the user or is initiating a CSfallback procedure. The MSC extends the time of waiting for the CSpaging response from the called UE, and returns an alerting message ofCS call link setup to the calling party according to a preset policy.

Alternatively, step 203 in this embodiment may be performed while theMME sends a CS paging notification message to the called UE in step 202.

Generally, the time limit set by the paging waiting timer on the MSC(including the retransmission time) depends on the time limit for theMSC to wait for the paging response from the UE, and the number ofpaging retransmissions on the MSC. For example, if the time limit forthe MSC to wait for the paging response from the UE is 5 seconds, andthe number of paging retransmissions on the MSC is 3, the time limit ofthe paging waiting timer is 15 seconds. If the MSC still receives nopaging response from the called UE upon expiry of the timer, the MSC inthe prior art terminates the call because it believes a failure to pagethe UE on the E-UTRAN, and returns an error message to the callingparty. Alternatively, the MSC believes that the called UE is out of thecoverage area of the E-UTRAN, and pages the called UE on the UTRANagain. However, the called UE is actually located in the coverage areaof the E-UTRAN at this time. Paging the called UE on the UTRAN againincreases the radio load on the UTRAN, and leads to a failure to pagethe called UE. Meanwhile, because the user of the calling UE hears noring back tone in a long time, the user may believe that the networkfails and terminates the call actively.

The MSC in this embodiment obtains the called-UE paging status messagereturned by the MME before receiving the paging response from the calledUE, and knows beforehand that the CS paging request message has beensuccessfully delivered to the called UE that is connected, but the userof the called UE has not confirmed whether to execute the CS fallbackprocedure or the CS paging response or service request message carryingthe cause of rejection has not arrived at the MSC though whether toexecute the CS fallback procedure has been confirmed. Therefore, the MSCgoes on waiting for a paging response from the called UE, withoutterminating the call or attempting the paging on the 2G/3G accessnetwork instead. Moreover, the MSC can send an alerting message to thecalling party at proper time beforehand when the UE is unable to respondto the CS paging request in time, which prevents the calling party fromterminating the call actively and improves the call success ratio.

In this embodiment, after the MME receives the paging request messagefrom the MSC, if the MME finds that the called UE is connected, the MMEnot only sends a CS paging notification message to the called UE, butalso returns a paging status message to the MSC, indicating that thecalled UE has received the paging notification message. In this way, thefollowing case can be prevented and therefore the call success ratio isimproved: The MSC performs an incorrect operation as a result ofmistakenly believing that paging the called UE on the E-UTRAN fails whenthe called UE waits for the user to confirm execution of the CS fallbackprocedure. In addition, the MSC may return an alerting message to thecalling party according to a preset policy. In this way, while thecalled UE waits for the user to confirm execution of the CS fallbackprocedure, the user of the calling UE never terminates the call as aresult of mistakenly believing no response from the called user.

FIG. 3 is a flowchart of a paging processing method provided in thethird embodiment of the present invention. In this embodiment, thecalled UE accesses the EPC currently through an E-UTRAN, and the calledMME is associated with the terminating MSC through an SGs interface. Asshown in FIG. 3, the method in this embodiment includes the followingsteps.

Step 301: The terminating MSC receives an IAM from the calling party,where the IAM carries an MSISDN of the called UE. The MSC searches thecontext of the called UE according to the called UE MSISDN carried inthe IAM, and obtains an IMSI corresponding to the called UE. The MSCsends a paging request message to the called MME, where the pagingrequest message carries the IMSI of the called UE.

The IAM may further carry an ID of the calling UE, for example, theMSISDN of the calling UE. In this case, the paging request messagecarries the ID of the calling UE accordingly.

Step 302: The MME receives the paging request message, searches thecontext of the called UE according to the called UE IMSI carried in thepaging request message, and sends a CS paging notification message tothe called UE through a NAS message when the MME determines that thecalled UE is connected according to the status recorded in the contextof the called UE.

If the paging request message sent by the MSC in step 301 carries the IDof the calling UE, namely, the MME obtains the ID of the calling UE fromthe MSC, for example, the MSISDN of the calling UE, the MME in this stepmay add the MSISDN of the calling UE to the CS paging notificationmessage.

Step 303: The called UE receives a CS paging notification message, anddecides to display prompt information according to preset CS fallbackconfiguration information, requesting the user to confirm whether toexecute a CS fallback procedure. Further, the called UE returns awaiting indication message to the MME, indicating that the called UE hasstarted a man-machine interaction program.

If the CS paging notification message sent by the MME in step 302carries the ID of the calling UE, namely, the called UE obtains the IDof the calling UE from the MME, for example, the MSISDN of the callingUE, the called UE in this step may add the MSISDN of the calling UE tothe prompt information.

Step 304: The MME receives the waiting indication message and returns acalled-UE paging status message to the MSC, indicating that the calledUE has received the paging notification message and has started aman-machine interaction program.

Step 305: The MSC receives the paging status message, extends time ofwaiting for the CS paging response from the called UE, and returns analerting message (namely, an ACM) of CS call link setup to the callingMSC according to the preset policy so that the calling MSC forwards thealerting message to the calling UE.

Step 306: The called UE receives a CS paging notification message, anddisplays prompt information according to preset CS fallbackconfiguration information, requesting the user to confirm whether toexecute a CS fallback procedure.

Step 307: After receiving an execution command input by the user,namely, a command for terminating the current data service andperforming the voice service, the called UE records a user selection,and sends a service request message to the eNB.

Step 308: The eNB receives the service request message and forwards itto the MME.

Step 309: The MME receives the service request message, and initiates aCS fallback procedure.

Till this step, the called UE falls back to the CS domain, sets up a CScall link for answering the call, and hands over the current PS bearerto the UTRAN and suspends it.

In step 303 in this embodiment, the CS fallback configurationinformation may be “always answer the call first”, and therefore, afterreceiving the CS paging notification message, the called UE decides notto display prompt information, but to confirm execution of a CS fallbackprocedure directly. Alternatively, the CS fallback configurationinformation may be “always request the user to confirm”, and therefore,after receiving the CS paging notification message, the called UEdecides to display prompt information that instructs the user to confirmwhether to execute a CS fallback procedure. The CS fallbackconfiguration information may be “request the user to confirm when theUE performs a packet service that permits no interruption (such asonline video or game)”, and therefore, when the called UE receives theCS paging notification message in the process of a non-interruptiblepacket service, the called UE decides to display prompt information thatinstructs the user to confirm whether to execute a CS fallbackprocedure. Alternatively, the CS fallback configuration information maybe “always answer the call with priority for the calling UEs on aspecific white list; or always reject calls for the calling UEs on aspecific blacklist; or request the user to confirm for the calling UEson neither the white list nor the blacklist”, and therefore, after thecalled UE receives the CS paging notification message triggered by thecalling UE on the specific white list, the called UE decides not todisplay the prompt information, but to confirm execution of a CSfallback procedure directly; after the called UE receives the CS pagingnotification message triggered by the calling UE on the specificblacklist, the called UE decides not to display the prompt information,but to reject the CS fallback procedure directly; after the called UEreceives the CS paging notification message triggered by other callingUEs, the called UE decides to display the prompt information thatinstructs the user to confirm whether to execute the CS fallbackprocedure. When the called UE decides to display the prompt information,the called UE returns a waiting indication message to the MME, so as tonotify the MME that the called UE has started a man-machine interactionprogram, and it may take a long time to respond to the paging request ofthe MSC no matter whether the user of the called UE decides to executethe CS fallback procedure or reject the CS fallback procedure. If thecalled UE believes no need of displaying the prompt information, thecalled UE confirms execution of the CS fallback procedure or rejects theCS fallback procedure directly, and the called UE in this step does notneed to return a waiting indication message to the MME, but starts a CSfallback procedure directly. Before receiving the waiting indicationmessage from the UE, the MME does not return the called-UE paging statusmessage to the MSC.

Nevertheless, the technical solution under the present invention doesnot exclude this possibility: The called UE still sends a waitingindication message to the MME even if deciding not to display the promptinformation after receiving the CS paging request message from the MME.

Similarly to the second embodiment, step 304 in this embodiment may beperformed in two modes: The MME returns the called-UE paging statusmessage to the MSC immediately after receiving the waiting indicationmessage; or, after receiving the waiting indication message, the MMEstarts a timer, and returns the called-UE paging status message to theMSC after expiry of the timer.

This embodiment differs from the second embodiment in that: The MME inthis embodiment negotiates with the called UE before returning the UEpaging status message to the MSC. That is, according to the waitingindication message received from the called UE, if the MME determinesthat the called UE has started a man-machine interaction program thatinstructs the user to confirm whether to execute the CS fallbackprocedure, the MME returns the called-UE paging status message to theMSC, indicating the paging status information of the called UE. If theMME determines that the called UE starts no man-machine interactionprogram that instructs the user to confirm whether to execute the CSfallback procedure, the MSC waits for the paging response as usualaccording to a normal procedure, without extending the time of waitingfor the paging response; or the MSC sends the alerting message to thecalling party beforehand.

As mentioned in the third embodiment of the present invention, after theUE currently connected on the E-UTRAN receives the CS pagingnotification message from the MME, the UE may decide whether to displaythe prompt information that instructs the user to confirm whether toexecute the CS fallback procedure, depending on the configurationspecified in the message and the packet service status. However, theuser experience is affected. If the user of the UE confirms execution ofthe CS fallback procedure, the user believes that the call has beenanswered according to the experience in the existing CS calls. However,in some CS supplementary services such as the call forwarding serviceand call deflection service, it is not appropriate for the user of thecalled UE to judge whether to answer the call according to the telephonenumber of the called UE alone.

In the call forwarding service, when user A of the calling UE originatesa call to user B, the service data of user B (forwarding party) is setto “forward the call to user C”, and therefore, the UE of user Cdisplays the prompt information that is the calling party information,namely, the telephone number of user A. However, it is possible thatuser C is willing to answer the call of user A, but is not willing tohear any call forwarded by user B. If it is necessary to confirm directanswering of the call when the called user C is requested to confirm theCS fallback, the called user is deprived of the right of choosing toanswer the call according to the forwarding-party information in thecall forwarding service. In the call deflection service, when user A ofthe calling UE originates a call to user B, after the UE rings, user Binputs the MSISDN of user C on the UE to forward the call to user C. Thecall deflection service differs from the call forwarding service inthat: In the call deflection service, the intermediate user B needs toinput the telephone number of the user C before choosing to “accept” theconversation, and confirm execution of call deflection; in the calldeflection service, the call from user A to user B is an ordinary call,and therefore, the MSC is unable to determine whether user B willinitiate call deflection or not before user B performs operations. Thecall deflection operation involves interactions between the UE and theMSC. If the prompt information gives only two operation options (namely,“answer” or “reject” the voice call) when requesting the user of thecalled UE to confirm the CS fallback procedure, and gives no option ofthe call deflection operation, the CS fallback solution deprives theuser of the right of using the call deflection service.

FIG. 4 is a flowchart of a paging processing method provided in thefourth embodiment of the present invention. In this embodiment, thecalled UE accesses the EPC currently through an E-UTRAN, and the calledMME is associated with the terminating MSC through an SGs interface. Asshown in FIG. 4, the method in this embodiment includes the followingsteps.

Step 401: The terminating MSC receives an IAM from the calling party,where the IAM carries an MSISDN of the called UE. The MSC searches thecontext of the called UE according to the called UE MSISDN carried inthe IAM, and obtains an IMSI corresponding to the called UE. The MSCsends a paging request message to the called MME, where the pagingrequest message carries the IMSI of the called UE and the service typeID.

The service type ID may represent an ordinary voice call, or any type ofsupplementary services such as the call forwarding service. As mentionedabove, whether the called user initiates the call deflection servicecompletely depends on the operation of the called user. Before this, theMSC processes the call as an ordinary call. Therefore, the service typeID does not represent a call deflection service. In the subsequentprocedure, according to the service type represented by the service typeID and the configuration information on the called UE, the called UE maydetermine whether the prompt information needs to be displayed for thisservice type again after the called UE falls back to the CS domain. Theprompt information instructs the user of the called UE to confirmwhether to answer the call.

This service type ID may be an ID indicating whether to display promptinformation again. That is, after the MSC judges the service type, theMSC indicates whether it is necessary to display the prompt informationagain after the called UE falls back to the CS domain. The promptinformation instructs the user of the called UE to confirm whether toanswer the call. For example, for an ordinary voice call, the MSCgenerates an ID indicating no need of displaying prompt informationagain; for a call forwarding service, the MSC generates an ID indicatingthe need of displaying prompt information again.

The IAM may further carry the ID of the calling UE, for example, theMSISDN of the calling UE. In this case, the paging request messagecarries the ID of the calling UE accordingly.

Step 402: The MME receives the paging request message, searches thecontext of the called UE according to the called UE IMSI carried in thepaging request message, and sends a CS paging notification message tothe called UE through a NAS message when the MME determines that thecalled UE is connected according to the status recorded in the contextof the called UE.

If the paging request message sent by the MSC in step 401 carries thecall-related information such as the ID of the calling UE and servicetype ID, namely, the MME obtains the call-related information such asthe ID of the calling UE and service type ID from the MSC, the MME inthis step may add the related information to the CS paging notificationmessage.

Step 403: The MME returns a called-UE paging status message to the MSC,indicating that the called UE has received the paging notificationmessage and has started a man-machine interaction program.

The MME may return a paging status message of the called UE to the MSCimmediately; or negotiate with the called UE and then return a pagingstatus message of the called UE to the MSC according to a waitingindication message returned by the called UE, which are respectivelydescribed in the second embodiment and the third embodiment above.

Step 404: The MSC receives the paging status message, extends time ofwaiting for the CS paging response from the called UE, and returns analerting message (namely, an ACM) of CS call link setup to the callingparty according to the preset policy.

Step 405: The called UE receives a CS paging notification message, anddisplays the first prompt information according to the preset CSfallback configuration information and the service type ID carried inthe CS paging notification message. The first prompt informationinstructs the user to confirm whether to execute a CS fallbackprocedure. Further, the called UE determines the content of the firstprompt information according to the service type ID. For example:

When the service type in the CS paging notification message indicates noneed of further confirmation, the first prompt information displayed bythe called UE includes no content of requiring further confirmationbefore answering the call. That is, the prompt information is to requestthe user to confirm whether to answer the call directly. For example,the prompt information includes “You have a call from 13XXXXXXXXX. Doyou want to interrupt the current XXXX packet service and answer thiscall directly?”, and provides operation options such as “accept”,“reject” and “call deflection” for the user.

When the service type in the CS paging notification message indicatesthe need of further confirmation, the first prompt information displayedby the called UE includes the content of requiring further confirmationbefore answering the call. That is, the prompt information is to requestthe user to confirm whether to interrupt the current packet service andfall back to the CS domain, but not to confirm answering of the calldirectly. Instead, the user confirms whether to answer the call afterfallback to the CS domain. For example, the prompt information includes“You have a call from 13XXXXXXXXX, and this call is a call forwardingservice that may require you to confirm whether to answer the call afterreceiving the call information. Do you want to interrupt the currentXXXX packet service and receive the call information?”, and providesoperation options such as “accept” and “reject” for the user.

Step 406: The called UE obtains the first instruction, where the firstinstruction is input by the user according to the first promptinformation, records a user selection, and sends a service requestmessage to the eNB according to the first instruction.

Step 407: The eNB receives the service request message and forwards itto the MME.

Step 408: The MME receives the service request message, and initiates aCS fallback procedure.

Till this step, the called UE falls back to the CS domain and a CS calllink is set up.

Step 409: The called UE displays the second prompt information accordingto the service type ID and the first instruction.

Step 410: The called UE obtains the second instruction, where the firstinstruction is input by the user according to the second promptinformation, and returns a Connect message to the MSC according to thesecond instruction.

In this embodiment, if the service type ID represents a supplementaryservice that instructs the user to reconfirm whether to answer the callafter fallback to the CS domain, or if the service type ID represents anordinary service but the first instruction, where the first instructionis input by the user of the called UE according to the first promptinformation indicates the need of reconfirmation; and, if the userselects the “call deflection” option, after the CS call link is set up,the called UE may further display the second prompt information thatinstructs the user to reconfirm. If the user does not select the “calldeflection” option, it is not necessary to display the second promptinformation that instructs the user to reconfirm. In this case, thecalled UE may return a response indicative of accepting the callsignaling (Connect) to the MSC immediately after the CS call link is setup, and the called user may start the conversation directly.

In this embodiment, a delay of a few seconds occurs in the PS handover,the procedure for responding to the paging request in the CS domain, andthe procedure for setting up a CS call link during the CS fallback. Inthis period, the CS call link between the user of the called UE and theuser of the calling UE is not connected, and the conversation is stilldisabled between both parties. That is, the called user is unable tohear the voice of the calling party, and the calling party is unable tohear the voice of the called user. In the existing CS voice service inthe prior art, after the called user presses the “accept” key, becausethe CS paging link has been set up, the conversation can startimmediately. To prevent the called user from mistakenly believing afailure to answer the call due to a failure to hear the voice of thecalling party when waiting for the CS fallback, the called UE may playsound information in the process of executing the CS fallback procedure.The sound information may be a special sound effect, indicating to theuser of the called UE that the call is being processed and that the userdoes not need to reattempt the call before completion of this soundeffect. To give a clearer prompt to the user of the called UE, thecalled UE may play different sound information for the call thatrequires no reconfirmation and the call that requires reconfirmationrespectively.

The paging request message sent by the MSC to the MME should be assimple as practicable, and generally carry the general call informationsuch as the ID of the called UE and the ID of the calling UE. However,the CS supplementary services involve a lot of special call-relatedinformation, for example, the forwarding-party ID in the call forwardingservice. However, after fallback to the CS domain, the called UE obtainscomplete call-related service information in the CS domain from the MSCin the process of setting up the call link. The displayed second promptinformation may include richer information content, and the user of thecalled UE can judge whether to answer the call more accurately.

For example, for the call forwarding service, the user of the called UEjudges whether to answer the paging according to the displayedforwarding-party number; after fallback to the CS domain, the called UEinteracts with the MSC directly according to the existing CS callprocedure, and the prompt information provides operation options inaddition to “accept” or “reject” for the user of the called UE, thuskeeping consistent with the existing CS service processing logics andproviding the same service capabilities; in the call deflection service,the user of the called UE may select a new number and forward the callto this new number.

In this embodiment, the service type ID of the MSC determines thecontent and operation options in the first prompt information displayedon the E-UTRAN; and the service type ID of the MSC and the operationoption selected by the user according to the first prompt informationdetermine whether to display the second prompt information after thecalled UE falls back to the CS domain, where the second promptinformation instructs the user to reconfirm. In this way, through the CSfallback solution, the user experience is consistent with the experiencein the existing CS service as far as possible, and the CS supplementaryservice operation options available to the user of the called UE are thesame as the operation options in the existing CS service.

FIG. 5 is a flowchart of an information displaying method provided inthe fifth embodiment of the present invention. In this embodiment, thecalled UE accesses the EPC currently through an E-UTRAN, and the calledMME is associated with the terminating MSC through an SGs interface. Asshown in FIG. 5, the method in this embodiment includes the followingsteps.

Step 501: The called UE receives a paging notification message thatcarries a service type ID.

The service type ID may represent an ordinary voice call, or any type ofthe supplementary services such as a call forwarding service. Asmentioned above, whether the called user initiates the call deflectionservice completely depends on the operation of the called user. Beforethis, the MSC processes the call as an ordinary call. Therefore, theservice type ID does not represent a call deflection service. In thesubsequent procedure, according to the service type represented by theservice type ID and the configuration information on the called UE, thecalled UE may determine whether the prompt information needs to bedisplayed for this service type again after the called UE falls back tothe CS domain. The prompt information instructs the user of the calledUE to confirm whether to answer the call.

This service type ID may be an ID indicating whether to display promptinformation again. That is, after the MSC judges the service type, theMSC indicates whether it is necessary to display the prompt informationagain after the called UE falls back to the CS domain. The promptinformation instructs the user of the called UE to confirm whether toanswer the call. For example, for an ordinary voice call, the MSCgenerates an ID indicating no need of displaying prompt informationagain; for a call forwarding service, the MSC generates an ID indicatingthe need of displaying prompt information again.

Step 502: The called UE displays the first prompt information accordingto the preset CS fallback configuration information and the service typeID carried in the CS paging notification message. The first promptinformation instructs the user to confirm whether to execute a CSfallback procedure. Further, the called UE determines the content of thefirst prompt information according to the service type ID. For example:

When the service type in the CS paging notification message indicates noneed of further confirmation, the first prompt information displayed bythe called UE includes no content of requiring further confirmationbefore answering the call. That is, the prompt information is to requestthe user to confirm whether to answer the call directly. For example,the prompt information includes “You have a call from 13XXXXXXXXX. Doyou want to interrupt the current XXXX packet service and answer thiscall?”, and provides operation options such as “accept”, “reject” and“call deflection” for the user.

When the service type in the CS paging notification message indicatesthe need of further confirmation, the first prompt information displayedby the called UE includes the content of requiring further confirmationbefore answering the call. That is, the prompt information is to requestthe user to confirm whether to interrupt the current packet service andfall back to the CS domain, but not to confirm answering of the calldirectly. Instead, the user confirms whether to answer the call afterfallback to the CS domain. For example, the prompt information includes“You have a call from 13XXXXXXXXX, and this call is a call forwardingservice that may require you to confirm whether to answer the call afterreceiving the call information. Do you want to interrupt the currentXXXX packet service and receive the call information?”, and providesoperation options such as “accept” and “reject” for the user.

Step 503: The called UE obtains a first instruction, where the firstinstruction is input by the user according to the first promptinformation.

Step 504: The called UE triggers execution of the CS fallback procedureaccording to the first instruction.

Step 505: The called UE displays the second prompt information accordingto the service type ID and the first instruction, where the secondprompt information instructs the user to confirm whether to put througha call.

Step 506: The called UE obtains a second instruction, where the firstinstruction is input by the user according to the second promptinformation.

Step 507: The called UE returns a Connect message to the MSC to putthrough the call according to the second instruction, or executes anoperation procedure corresponding to the service type ID.

In this embodiment, if the service type ID represents a supplementaryservice that instructs the user to reconfirm whether to answer the callafter fallback to the CS domain, or if the service type ID represents anordinary service but the first instruction, where the first instructionis input by the user of the called UE according to the first promptinformation indicates the need of reconfirmation; and, if the userselects the “call deflection” option, after the CS call link is set up,the called UE may further display the second prompt information thatinstructs the user to reconfirm. If the user does not select the “calldeflection” option, it is not necessary to display the second promptinformation that instructs the user to reconfirm. In this case, thecalled UE may return a response indicative of accepting the callsignaling (Connect) to the MSC immediately after the CS call link is setup, and the called user may start the conversation directly.

In this embodiment, a delay of a few seconds occurs in the PS handover,the procedure for responding to the paging request in the CS domain, andthe procedure for setting up a CS call link during the CS fallback. Inthis period, the CS call link between the user of the called UE and theuser of the calling UE is not connected, and the conversation is stilldisabled between both parties. That is, the called user is unable tohear the voice of the calling party, and the calling party is unable tohear the voice of the called user. In the existing CS voice service inthe prior art, after the called user presses the “accept” key, becausethe CS paging link has been set up, the conversation can startimmediately. To prevent the called user from mistakenly believing afailure to answer the call due to a failure to hear the voice of thecalling party when waiting for the CS fallback, the called UE may playsound information in the process of executing the CS fallback procedure.The sound information may be a special sound effect, indicating to theuser of the called UE that the call is being processed and that the userdoes not need to reattempt the call before completion of this soundeffect. To give a clearer prompt to the user of the called UE, thecalled UE may play different sound information for the call thatrequires no reconfirmation and the call that requires reconfirmationrespectively.

In this embodiment, the paging notification message received by thecalled UE is triggered by the paging request message sent by the MSC tothe MME. The paging request message sent by the MSC to the MME should beas simple as practicable, and generally carry only the general callinformation such as the ID of the called UE and the ID of the callingUE. However, the CS supplementary services involve a lot of specialcall-related information, for example, the forwarding-party ID in thecall forwarding service. However, after fallback to the CS domain, thecalled UE obtains complete call-related service information in the CSdomain from the MSC in the process of setting up the call link. Thedisplayed second prompt information may include richer informationcontent, and the user of the called UE can judge whether to answer thecall more accurately.

For example, for the call forwarding service, the user of the called UEjudges whether to answer the paging according to the displayedforwarding-party number; after fallback to the CS domain, the called UEinteracts with the MSC directly according to the existing CS callprocedure, and the prompt information provides operation options inaddition to “accept” or “reject” for the user of the called UE, thuskeeping consistent with the existing CS service processing logics andproviding the same service capabilities; in the call deflection service,the user of the called UE may select a new number and forward the callto this new number.

In this embodiment, the service type ID of the MSC determines thecontent and operation options in the first prompt information displayedon the E-UTRAN; and the service type ID of the MSC and the operationoption selected by the user according to the first prompt informationdetermine whether to display the second prompt information after thecalled UE falls back to the CS domain, where the second promptinformation instructs the user to reconfirm. In this way, through the CSfallback solution, the user experience is consistent with the experiencein the existing CS service as far as possible, and the CS supplementaryservice operation options available to the user of the called UE are thesame as the operation options in the existing CS service.

FIG. 6 shows a structure of a mobility management apparatus provided inthe sixth embodiment of the present invention. As shown in FIG. 6, themobility management apparatus in this embodiment includes a firstreceiving module 61 and a notifying module 62, which are connected toeach other. The first receiving module 61 receives a paging requestmessage sent by an MSC server which the called UE registers to, namely,the terminating MSC, where the paging request message may carry the IDof the called UE (such as the IMSI of the called UE). When the called UEis connected, the notifying module 62 sends a paging notificationmessage to the called UE according to the paging request messagereceived by the first receiving module 61, and returns a called-UEpaging status message to the MSC server, indicating that the called UEhas received the paging notification message.

The mobility management apparatus provided in this embodiment may be anMME in the EPS. After the first receiving module of the MME receives thepaging request message from the terminating MSC, if the notifying modulefinds that the called UE is connected, the notifying module not onlysends a CS paging notification message to the called UE, but alsoreturns a paging status message to the MSC, indicating that the calledUE has received the paging notification message. The paging statusmessage may be sent at the time of sending the CS paging notificationmessage, or sent after a time limit of waiting if no message indicativeof accepting or rejecting the CS fallback procedure is received from thecalled UE within the time limit of waiting. In this way, the followingcase can be prevented and therefore the call success ratio is improved:The MSC performs an incorrect operation as a result of mistakenlybelieving that paging the called UE on the E-UTRAN fails when the calledUE waits for the user to confirm execution of the CS fallback procedure.

FIG. 7 shows a structure of a mobility management apparatus provided inthe seventh embodiment of the present invention. As shown in FIG. 7, themobility management apparatus in this embodiment may further include: atriggering module 63, connected to the notifying module 62, andconfigured to obtain the waiting indication message from the called UEand trigger the notifying module 62 to return a called-UE paging statusmessage to the MSC server.

The difference from the previous embodiment is: The notifying module inthis embodiment negotiates with the called UE before returning the UEpaging status message to the MSC. That is, depending on the waitingindication message received from the called UE, if the triggering moduledetermines that the called UE has started a man-machine interactionprogram that instructs the user to confirm whether to execute the CSfallback procedure, the triggering module triggers the notifying moduleto return the called-UE paging status message to the MSC, indicating thepaging status information of the called UE. If the triggering moduledetermines that the called UE starts no man-machine interaction programthat instructs the user to confirm whether to execute the CS fallbackprocedure, the triggering module does not trigger the notifying moduleto return the called-UE paging status message to the MSC, and the MSCwaits for the paging response as usual according to a normal procedure,without extending the time of waiting for the paging response; or theMSC performs the step of sending the alerting message to the callingparty beforehand.

FIG. 8 shows a structure of an MSC server provided in the eighthembodiment of the present invention. As shown in FIG. 8, the MSC serverin this embodiment may include: a second receiving module 81, configuredto receive a called-UE paging status message returned by a mobilitymanagement apparatus; and a processing module 82, configured to extendtime of waiting for a called UE to return a paging response messageaccording to the paging status message received by the second receivingmodule 81.

The MSC server provided in this embodiment may be an MSC in the CSdomain. The MSC receives the paging status message from the MME, andknows that the called UE has received the paging notification message.In this way, the following case can be prevented and therefore the callsuccess ratio is improved: The MSC performs an incorrect operation as aresult of mistakenly believing that paging the called UE on the E-UTRANfails when the called UE waits for the user to confirm execution of theCS fallback procedure.

Further, the processing module 82 may return an alerting message of theCS call link setup to the MSC server which the calling UE registers toaccording to a policy. In this way, while the called UE waits for theuser to confirm execution of the CS fallback procedure, the user of thecalling UE never terminates the call as a result of mistakenly believingno response from the called user.

FIG. 9 shows a structure of a UE provided in the ninth embodiment of thepresent invention. As shown in FIG. 9, the UE in this embodiment mayinclude: a third receiving module 91, configured to receive a pagingnotification message that carries a service type ID; a first displayingmodule 92, configured to display first prompt information after thethird receiving module 91 receives the paging notification message,where the first prompt information instructs a user to confirm whetherto accept a CS fallback procedure; a first obtaining module 93,configured to obtain a first instruction, where the first instruction isinput by the user according to the first prompt information; a firstexecuting module 94, configured to trigger execution of the CS fallbackprocedure according to the first instruction; a second displaying module95, configured to display second prompt information according to theservice type ID and the first instruction, where the second promptinformation instructs the user to confirm whether to put through a call;a second obtaining module 96, configured to obtain a second instruction,where the first instruction is input by the user according to the secondprompt information; and a second executing module 97, configured toreturn a Connect message to the MSC server to put through the callaccording to the second instruction, or execute an operation procedurecorresponding to the service type ID.

In this embodiment, the service type ID of the MSC determines thecontent and operation options in the first prompt information displayedon the E-UTRAN; and the service type ID of the MSC and the operationoption selected by the user according to the first prompt informationdetermine whether to display the second prompt information after thecalled UE falls back to the CS domain, where the second promptinformation instructs the user to reconfirm. In this way, through the CSfallback solution, the user experience is consistent with the experiencein the existing CS service as far as possible, and the CS supplementaryservice operation options available to the user of the called UE are thesame as the operation options in the existing CS service.

FIG. 10 shows a structure of a paging processing system provided in thetenth embodiment of the present invention. As shown in FIG. 10, thepaging processing system in this embodiment may include: a called UE1001, registered with a mobility management apparatus 1003 and an MSCserver 1002 respectively, and configured to receive a pagingnotification message from the mobility management apparatus 1003; theMSC server 1002, configured to send a paging request message to themobility management apparatus 1003, where the paging request message maycarry the ID of the called UE (such as the IMSI of the called UE),receive the called-UE paging status message from the mobility managementapparatus 1003, and extend the time of waiting for the called UE toreturn the paging response message according to the paging statusmessage; and the mobility management apparatus 1003, configured toreceive the paging request message sent by the MSC server 1002, send apaging notification message to the called UE 1001 according to thepaging request message when the called UE is connected, and return thepaging status message of the called UE 1001 to the MSC server 1002 toindicate that the called UE 1001 has received the paging notificationmessage.

In this embodiment, the MSC server 1002 may be an MSC in the CS domain,and may be the MSC server provided in the eighth embodiment of thepresent invention; the mobility management apparatus 1003 may be an MMEin the EPS, and may be a mobility management apparatus provided in thesixth or seventh embodiment of the present invention; the called UE 1001may be the UE provided in the ninth embodiment of the present invention.In this embodiment, after the MME receives the paging request messagefrom the terminating MSC, if the MME finds that the called UE isconnected, the MME not only sends a CS paging notification message tothe called UE, but also returns a paging status message to the MSC,indicating that the called UE has received the paging notificationmessage. The paging status message may be sent at the time of sendingthe CS paging notification message, or sent after a time limit ofwaiting if no message indicative of accepting or rejecting the CSfallback procedure is received from the called UE within the time limitof waiting. In this way, the following case can be prevented andtherefore the call success ratio is improved: The MSC performs anincorrect operation as a result of mistakenly believing that paging thecalled UE on the E-UTRAN fails when the called UE waits for the user toconfirm execution of the CS fallback procedure.

Further, the called UE in this embodiment may be further configured todisplay the first prompt information after receiving the CS pagingnotification message. The first prompt information instructs the user toconfirm whether to execute a CS fallback procedure. The called UEdetermines the first prompt information (content and operation options)according to the service type ID, obtains the first instruction, wherethe first instruction is input by the user of the called UE according tothe first prompt information, and triggers the mobility managementapparatus to execute the CS fallback procedure according to the firstinstruction.

The CS paging notification message received by the called UE may furthercarry a service type ID. Further, the called UE may be configured todisplay the second prompt information according to the service type IDand the first instruction, obtain the second instruction, where thefirst instruction is input by the user of the called UE according to thesecond prompt information, and return a Connect message to the MSCserver according to the second instruction to put through the call, orexecute the operation procedure corresponding to the service representedby the service type ID. In this embodiment, if the service type IDrepresents a supplementary service that instructs the user to reconfirmwhether to answer the call after fallback to the CS domain, or if theservice type ID represents an ordinary service but the firstinstruction, where the first instruction is input by the user of thecalled UE according to the first prompt information indicates the needof reconfirmation; and, if the user selects the “call deflection”option, after the CS call link is set up, the called UE may furtherdisplay the second prompt information that instructs the user toreconfirm. If the user does not select the “call deflection” option, itis not necessary to display the second prompt information that instructsthe user to reconfirm. In this case, the called UE may return a Connectmessage indicative of accepting the call signaling to the MSC serverimmediately after the CS call link is set up (namely, put through thecall directly), and the user of the called UE may start the conversationdirectly.

In this embodiment, the service type ID of the MSC determines thecontent and operation options in the first prompt information displayedon the E-UTRAN; and the service type ID of the MSC and the operationoption selected by the user according to the first prompt informationdetermine whether to display the second prompt information after thecalled UE falls back to the CS domain, where the second promptinformation instructs the user to reconfirm. In this way, through the CSfallback solution, the user experience is consistent with the experiencein the existing CS service as far as possible, and the CS supplementaryservice operation options available to the user of the called UE are thesame as the operation options in the existing CS service.

The PS domain and the CS domain in the embodiments above may be acombination of various PS systems and CS systems in the prior art. Forexample, the PS domain may be the PS domain of the GPRS, UMTS, EPS,WiMAX, and CDMA HRPD; and the CS domain may be the CS domain of the GSM(GERAN), WCDMA (UTRAN), and CDMA 1×RTT.

Persons of ordinary skill in the art should understand that all or partof the steps of the method according to the embodiments of the presentinvention may be implemented by a program instructing relevant hardware.The program may be stored in a computer readable storage medium. Whenthe program runs, the steps of the method according to the embodimentsof the present invention are performed. The storage medium may be anymedium that is capable of storing program codes, such as a Read-OnlyMemory (ROM), a Random Access Memory (RAM), a magnetic disk, or aCD-ROM.

Finally, it should be noted that the above embodiments are merelyprovided for describing the technical solution of the present invention,but not intended to limit the present invention. It is apparent thatpersons skilled in the art can make various modifications and variationsto the invention without departing from the spirit and scope of theinvention. The present invention is intended to cover the modificationsand variations provided that they fall within the scope of protectiondefined by the following claims or their equivalents.

What is claimed is:
 1. A non-transitory computer readable medium,comprising computer program code, which, when executed by a processor,causes the processor to: receive a paging request message from a MobileSwitching Center (MSC) server, wherein a called User Equipment (UE) hasregistered to the MSC server; determine, according to a status recordedin a context of the called UE, whether the called UE is connected to amobility management entity (MME); send a paging notification message tothe called UE in response to determining that the called UE is connectedto the MME; and send, to the MSC server, a message indicating a statusof communication between the called UE and the MME, in response todetermining that the called UE is connected to the MME, and withoutwaiting for a service request message from the called UE.
 2. Thenon-transitory computer readable medium according to claim 1, whereinthe computer program code, when executed by the processor, furthercauses the processor to: initiate a circuit-switched (CS) fallbackprocedure.
 3. The non-transitory computer readable medium according toclaim 1, wherein sending the paging notification message to the calledUE comprises: sending a circuit switched (CS) paging notificationmessage to the called UE through a Non Access Stratum (NAS) message. 4.The non-transitory computer readable medium according to claim 1,wherein the message indicating the status of communication between thecalled UE and the MME is a called UE paging status message.
 5. Thenon-transitory computer readable medium according to claim 1, whereinthe computer program code, when executed by the processor, furthercauses the processor to: receive the service request message from thecalled UE.
 6. A non-transitory computer readable medium, comprisingcomputer program code, which, when executed by a processor, causes theprocessor to: send a paging request message to a Mobility ManagementEntity (MME); receive, from the MME, a message indicating a status ofcommunication between a called user equipment (UE) and the MME, whereinthe message indicating the status of communication between the called UEand the MME is sent by the MME in response to a determination by the MMEthat the called UE is connected to the MME, and without the MME waitingfor a service request message from the called UE; and return an alertingmessage to a mobile switching center (MSC) server to which a calling UEhas registered, without waiting for a response from the called UE, afterreceiving the message indicating the status of communication between thecalled UE and the MME returned by the MME.
 7. The non-transitorycomputer readable medium according to claim 6, wherein returning thealerting message to the MSC server comprises: returning the alertingmessage to the MSC server to which the calling UE has registeredimmediately after receiving the message indicating the status ofcommunication between the called UE and the MME returned by the MME. 8.The non-transitory computer readable medium according to claim 1,wherein the message indicating the status of communication between thecalled UE and the MME is a called UE paging status message.